FR2685678A1 - COMPLEX FILM, PARTICULARLY FOR PACKAGING FOOD PRODUCTS AND METHOD OF MANUFACTURE. - Google Patents

Abstract

Complex film, in particular applicable to food products, characterized in that it comprises at least one moisture barrier support. coated with a layer of material acting as a barrier to gases, in particular to oxygen and a third layer of material, also barrier to humidity, primers being arranged between the different layers so as to allow good adhesion of the 'all layers on the support.

Description

The subject of the present invention is a film comprising

  plex, especially intended for the packaging of products

  food and the manufacturing process.

  Many complexes are known for use in

  baling of food products, these complexes having very varied characteristics depending on the

  type of food to protect.

  Indeed, these complexes have several roles, first they constitute the physical packaging of the product, they provide protection against

  external aggressions while playing the r 8 le de bar-

  which makes it possible to comply with the recommended hygienic conditions, while ensuring good

conservation of the product itself.

  In addition, the packaging is more and more

  used as a means of communication and publicity

  té so that it must be able to carry information

  tions performed in heliography or by any other

printing process.

  In the case of the present invention, the aim of the complex sought is to provide a gas barrier in general and more particularly a barrier to oxygen in the ambient air as well as a

moisture barrier.

  In addition, it is desirable that this complex does not release chlorine during an incineration, that it can be printed and heat sealed to allow a hermetic closure, and finally that it can

   be processed at high speed and automatically

  than. In terms of barrier properties, products are known which are barriers to oxygen when the humidity of the surrounding air is not

too important.

  Thus the copolymer of ethylene and al-

  cool vinyl called E V O H Or E / VAL according to ISO 1043 standard, forms an excellent barrier to

  gas, and more specifically oxygen,

  that it is dry but becomes very permeable to gases

  as soon as the humidity rate increases.

  So that this copolymer has a good seal

  tee with gases, and more particularly with oxygen, it is necessary to deposit it on a support, generally after having diluted it in a solvent, then the whole is dried and it is then necessary to obtain a good crystallization of this

copolymer.

  This crystallization is obtained as well as the

  provides for the implementation recommended by the manufacturers

  cants thanks to a heat treatment which consists, after drying and removal of the solvent, to bring to a temperature of the order of 150 the whole of the support and of the layer of VOH E We therefore understand the need to have a support that can

  withstand such temperatures without degradation.

  If supports such as polyamide or polyester films withstand such temperatures, it

  this is not the same for polypropylene films.

lene for example.

  It is therefore currently not possible to produce a layer by coating E VOH with a support which does not withstand a temperature at least equal to 1500. However, as has been indicated, E VOH which would not undergo no such heat treatment is even more sensitive to humidity and in this case, it no longer plays its role as a gas barrier and even less to oxygen, which is detrimental to the conservation of the food products contained in it. inside the packaging made from a

such complex.

  It is necessary to remember that the price of re-

  comes from a complex is important and any simpli-

  realization fication can introduce decreases

  sensitive which, multiplied by large quan-

  consumed, allow significant savings

  wheat. On the other hand, certain high-priced and temperature-resistant support films such as polyamide or polyester have poor resistance to humidity, while certain other lower-priced products resistant to temperatures below 150, such as polypropylene, on the other hand

  excellent moisture barrier qualities.

  The present invention therefore makes it possible to use any

  type of film because it removes any heat treatment

  mique at high temperature, it gives the packaging a high impermeability to humidity and gases, as well as a possibility of heat sealability and

  it can be printed on the front but also on the back.

  To this end, the complex film according to the invention, in particular applicable to food products,

  characterized in that it comprises at least one sup-

  moisture barrier, coated with a layer of

  material acting as a gas barrier, in particular

  oxygen, and a third layer of material

  re also moisture barrier, primers being arranged between the different layers so as to allow good adhesion of the assembly

layers on the support.

  According to a particular embodiment of the in-

  In particular, the layer acting as an oxygen barrier is a copolymer of ethylene and vinyl alcohol. As for the support, it is chosen, for example, from any of the following films: oriented, pure, co-extruded or coated polypropylene or polyester films, oriented polyamide films, coated cellulosic films with a third layer, in particular barrier welding films moisture based on polyethylene,

polypropylene or ionomer.

  According to another characteristic of the invention, the moisture barrier layer disposed on the oxygen barrier layer is a coating

ionomer or polyolefin.

  According to a preferred embodiment of the invention, the complex comprises from the outside to the inside, a support film of coextruded polypropylene, a first primer of the two-component polyurethane type, a layer of copolymer of ethylene and of vinyl alcohol, a second primary also of the type

  two-component polyurethane and an ionomer coating

re.

  The manufacturing process of the complex according to the

  vention consists in depositing a two-component polyurethane primer on the support, drying this primer, coating E V O H. diluted in a solvent, evaporating the solvent at a temperature compatible with the support, drying

  eventually the film until you get a crystal-

  Sufficient coating of the E V O H layer and then adding a welding film of polypropylene for example or a moisture barrier coating, preceded by a primer, so as to obtain a

  thermosealability of the product on itself.

  According to another characteristic of the process, the im-

  pressure is applied directly to the layer of E V O H before applying the moisture barrier film or directly to the primer added to the E V O H

  The process and the resulting product are described below.

  after with reference to Figures 1 and 2 which represent

  schematically the complex film according to the

  vention, FIG. 2 being an alternative embodiment

tion of the process of Figure 1.

  In FIG. 1, we have represented diagrammatically

  only a complex film according to the invention.

  From outside to inside, there is thus a support film 10, a first primer 12, a layer of gas barrier material, in particular to oxygen 14, a second primer 16, an impression

18 and a second coating 20.

  In the preferred embodiment shown in

  Figure 1, the support film is a polypropylene film

  lene on which is deposited a primer of the two-component polyurethane type which will allow good adhesion and good wettability of the layer 14 which is in the present case a layer of

  copolymer of ethylene and vinyl alcohol

  specialized in particular under the name "SOARNOL".

  This copolymer must first be diluted in suitable solvents and then the entire film, the primer and the coating of E V O H is

  dried at a temperature compatible with polypro-

  pylene until the solvent has evaporated.

  Additional baking of the whole at a temperature between 50 and 100 C for

  several days makes it possible to obtain a good crystal-

  reading. The second primer which allows the bonding of the following layers is also a two-component polyurethane, in particular sold under the brand "LAMAL" and on this primer, a

  coating with a moisture barrier material

  which can be of the ionomer type such as

  product marketed under the name "SUR-

  LYNE "more particularly in the form of disper-

water or polyolefin.

  In the case where it is necessary to carry out a printing such as referenced in 18, this is carried out directly on the primer using

  specific inks of known type.

  It can therefore be seen that the food product contained within this complex is isolated from the inks

  printing by ionomer or polyole coating

  final. According to a variant shown in Figure 2, we have from the outside to the inside the

layers 22, 24, 26, 28 30 and 32.

  Layer 22 is a support film of the polypropylene type.

  the co-extruded lene to which a primer identical to layer 12 is attached, similar to the layer of E V O H which is deposited in the same way and

  produced as layer 14 in FIG. 1.

  The layer 28 corresponding to the printing can be produced directly on the E V O H layer on

  which is deposited an adhesive 30 such as a polyurethane

  two-component rethane marketed under the name

  LAMAL nation which allows good adhesion of the

  layer of moisture barrier material.

  In this alternative embodiment, the layer of moisture barrier material 32 is a film

  welding in polypropylene-based copolymer.

  There is thus the possibility of sealing the packages flesh on flesh or flesh on skin, that is to say that the moisture barrier layer 20 or 32 can be

  sealed either on itself or on the film above

  Harbor. In this case also the printing ink is isolated from the food product by the adhesive 30 and the film.

welding 32.

  We also note that in this case the reading

  takes place from outside to inside through

  towards the film, the first primer and the layer of E V O H. Another important advantage of the invention is that of isolating the impression from the outside, so that the friction of the packages on themselves does not

  not cause deterioration of prints.

  Thus, the invention, two examples of which have been described in detail above, can be achieved by implementing the method according to the invention and by choosing to combine, for example, the following supports: oriented, pure, co-oriented polypropylene or polyester films -extruded or coated, oriented polyamide films, coated cellulosic films with, as a third layer, in particular the moisture barrier films based on polyethylene,

polypropylene or ionomer.

Claims (6)

  1 Complex film, in particular applicable to food products, characterized in that it   includes at least one moisture barrier support.   coated with a layer of chlorine-free material acting as a barrier to gases, in particular oxygen and a third layer of material, also barrier to humidity, primers or adhesives being placed between the different layers so as to allow good adhesion of   all the layers on the support.   2 Film according to claim 1, charac-   terized in that the layer acting as a bar-   gas and especially oxygen is a co-   polymer of ethylene and vinyl alcohol.   3 Film according to claim 1 or 2,   characterized in that the moisture barrier support   dity is chosen from any one of the polypropylene films or pure polyesters, co-extruded or   coatings, oriented polyamides or cel films coated lulosics.   4 Film according to any one of the res-   dications previous characterized in that the moisture barrier layer is disposed on the gas barrier layer and in particular to oxygen   is an ionomer or polyolefin coating.   Film according to any one of the preceding claims, characterized in that it comprises, from the outside to the inside, a polypropylene support film, a first primer of the two-component polyurethane type, a layer of ethylene copolymer and vinyl alcohol, a   second adhesive primer also of the polyu-   1- two-component rethane and an ionomer coating moisture barrier.   6 Film production process according to   any one of claims 1 to 5, charac-   terized in that a moisture barrier support is coated with a layer of gas barrier product, in particular oxygen, free of chlorine, this layer of gas barrier product itself being covered with a barrier material to humidity.   7 Method according to claim 6, charac-   terrified in that it consists of depositing a primary   two-component polyurethane type on a top film   port, to dry this primer, to make a coating   ion of V O H diluted in solvents, to be evaporated from the latter at a temperature compatible with the   support, to steam the film until a crisp   Sufficient tallization of the E V O H layer.   before covering with a barrier material dity.   a Method according to claim 7, charac-   that the moisture barrier coating   is replaced by a welding film, also bar- laugh at humidity.